Iodine producer Iofina has completed its latest iodine extraction plant in the US, but it said construction of more plants would be delayed.Iofina, which produces iodine in Texas, Montana and Oklahoma, said it had finished building its IO#5 plant and was awaiting final regulatory approval.The group is also building IO#6 and expects to complete it in the second quarter of this year, giving it four similar purpose sites in addition to IO#1 and IO#2.However, Iofina said it was planning to do an operational review before starting work on more full-scale plants.The review, scheduled for completion in the autumn, will identify potential improvements to construction methodology, cost reductions, improvement in completion times and the ideal size of plants."Construction of further full-size plants will be delayed until this review is complete, which will reduce short term capital expenditures and improve cash flows," Iofina said.Shares in Iofina fell 9p or 14.3% to 54p by 15:32 in London.PW